As an OH-23 pilot with the 123rd Aviation Battalion, CWO Hugh Thompson flew over the Vietnamese village of My Lai on March 16, 1968, as U.S. troops were killing civilians.

When Thompson landed and tried to get 1LT William Calley to stop the killing, Calley said he was in charge and sent Thompson on his way. Continuing to fly around the area, he and his crew spotted some Vietnamese trying to hide. He landed and, with crewmen Larry Colburn and Glenn Andreotta covering him, pulled out of hiding nine people facing certain death and evacuated them from the area. Thompson then went to his aviation company commander, MAJ Fred Watke, and reported what he had seen. Watke reported the massacre to the ground task force commander, who ordered an immediate cease fire.

After My Lai, Thompson's aircraft took hits on eight missions and four helicopters were lost to battle damage. Thompson was shot down during a later mission and was evacuated in traction with a broken back. For his actions at My Lai he was vilified by supporters of the massacre, both inside and outside the U.S. government.

Thompson later accepted a commission and attained the rank of captain, but served his remaining active-duty time as a warrant officer because of post-war reductions in force. In March 1998 the Army belatedly recognized Thompson's heroic actions at My Lai with the award of the Soldier's Medal.